In the words of Alain Meilland in the foreword of the Encyclopedia of Rose Science: “no other flower is as universally loved and grown or has a more illustrious history than the rose” (Meilland, 2003). Rose is a member of one of the most important horticultural families, the rose family (Rosaceae) and is admired for its great diversity of floral and plant characteristics. Sales of roses in 2014 in the United States generated $203.5 million from the production of 36.6 million plants by 1808 growers (U.S. Department of Agriculture, 2015). According to the Green Industry Research Consortium National Survey, roses accounted for 3% of overall sales from 18 different horticultural production crop categories of the industry worth $25.9 billion. Rose industry sales equate to contributions to the U.S. economy of ≈$777 million. Most roses (65%) are sold through retail outlets, with the remaining 35% of rose sales coming from landscape services (Green Industry Research Consortium, 2013). In North America, the economic impact of landscape roses in Canada was estimated at $149 million, and the value in the United States was estimated at $928 million (Vineland Research and Innovation Centre, 2013). The rose industry has a large economic impact worldwide.
Rose has four subgenera, more than 100 species (diploid through decaploid) and more than 30,000 commercial cultivars (mostly diploid, triploid, and tetraploid). These cultivars exhibit wide interspecific and intraspecific cross compatibility (Blechert and Debener, 2005; Byrne and Crane, 2003; Cairns, 2000; Jian et al., 2010; Spiller et al., 2011; Ueckert et al., 2015; Zlesak, 2009), and a broad diversity of flower and plant growth habits. Zuzek et al. (1995) described diverse growth habits of roses defining descriptors, including arching, climbing, dense, groundcover, open, rugosa, spreading, and suckering. Given this diversity of forms, the role roses play in landscapes is extensive. They are found adorning roadsides, public parks, commercial spaces, and residential areas. Garden roses provide aesthetic value throughout the growing season due to both their vegetative and floral production.
Plant architecture of roses is linked to flower yield and ornamental value (Crespel et al., 2014). Previous architectural analysis of roses focused on morphological, topological, and geometrical traits, such as stem length and diameter, succession, branching, and branching angles (Godin et al.,1999). Traits identified as relevant for characterizing rose bush shape include plant height, the number and length of stems, leaf profile, the internode length, branching angles, the branching site, and branch order number (Crespel et al., 2013; Gitonga et al., 2014; Kawamura et al., 2015; Morel et al., 2009; Wu et al., 2019). Little is known about which traits are critical to the selection of specific bush shapes.
The focus of the TAMU Rose Breeding and Genetics program is the development of garden roses for the modern garden. One of the most important trends in home landscapes and gardens is low maintenance, in other words, easy-care (American Nurseryman, 2016). A rose that is low maintenance needs to be resistant to both biotic and abiotic stresses and have a full plant structure without consistent pruning. Recent surveys and studies indicate that consumer preferences for new rose traits include disease resistance, compactness, moderate height (from waist to shoulder height is preferable), a high number of evenly distributed flowers, and fragrance (Boumaza et al., 2009; Chicago Botanic Garden, 2016; Lütken et al., 2015; Waliczek et al., 2018). The objectives of the Rose Breeding and Genetics Program are to develop disease-resistant, heat-tolerant, compact plants with high flower count that are uniformly distributed on the plant and produced throughout the growing season. This research aims to identify the key growth traits responsible for the compact structure of the rose plant.
American Nurseryman 2016 6 Standout landscaping trends for 2016. 12 May 2017. <http://www.amerinursery.com/landscape/six-standout-landscaping-trends-2016/>
Blechert, O. & Debener, T. 2005 Morphological characterization of the interaction between Diplocarpon rosae and various rose species Plant Pathol. 54 82 90
Boumaza, R., Demotes-Mainard, S., Huché-Thellier, L. & Guérin, V. 2009 Visual characterization of the aesthetic quality of the rose-bush J. Sens. Stud. 24 774 796
Byrne, D.H. & Crane, Y.M. 2003 Meiosis, p. 273–279. In: A.V. Roberts, T. Debener, and S. Gudin (eds.). Encyclopedia of rose science. Elsevier, Oxford, UK
Cairns, T. 2000 Modern roses XI, the world encyclopedia of roses. Academic Press, San Diego, CA
Chicago Botanic Garden 2016 Plant breeding. 25 July 2016. <http://www.chicagobotanic.org/research/ornamental_plant_research/plant_breeding>
Crespel, L., Le Bras, C., Relion, D. & Morel, P. 2014 Genotype × year interaction and broad-sense heritability of architectural characteristics in rose bush Plant Breed. 133 412 418
Crespel, L., Sigogne, M., Donès, N., Relion, D. & Morel, P. 2013 Identification of relevant morphological, topological and geometrical variables to characterize the architecture of rose bushes in relation to plant shape Euphytica 191 129 140
Gitonga, V.W., Koning-Boucoiran, C.F., Verlinden, K., Dolstra, O., Visser, R.G., Maliepaard, C. & Krens, F.A. 2014 Genetic variation, heritability and genotype by environment interaction of morphological traits in a tetraploid rose population BioMed Central Genet. 15 146 159
Godin, C., Costes, E. & Sinoquet, H. 1999 A method for describing plant architecture which integrates topology and geometry Ann. Bot. 84 343 357
Green Industry Research Consortium 2013 Trade flows and market practices within the U.S. nursery industry, 2013. 9 June 2019. <http://saaesd.ncsu.edu/docs/National%20Green%20Industry%20Survey%20report%202014%20SCSB%2052615.pdf>
Jian, H., Zhang, H., Tang, K., Li, S., Wang, Q., Zhang, T., Qiu, X. & Yan, H. 2010 Decaploidy in Rosa praelucens Byhouwer (Rosaceae) endemic to Zhongdian plateau, Yunnan, China Caryologica 63 162 167
Kawamura, K., Hibrand-Saint Oyant, L., Thouroude, T., Jeauffre, J. & Foucher, F. 2015 Inheritance of garden rose architecture and its association with flowering behaviour Tree Genet. Genomes 11 1 12
Lütken, H., Hegelund, J.N., Himmelboe, M., Lauridsen, U.B. & Müller, R. 2015 Natural transformation in plant breeding – A biotechnological platform for quality improvement of ornamental, agricultural and medicinal plants Acta Hort. 1087 19 28
Meilland, A. 2003 Foreword. In: A.V. Roberts, T. Debener, and S. Gudin (eds.). Encyclopedia of rose science. Elsevier, Oxford, UK
Morel, P., Galopin, G. & Dones, N. 2009 Using architectural analysis to compare the shape of two hybrid tea rose genotypes Scientia Hort. 120 391 398
Spiller, M., Linde, M., Hibrand-Saint Oyant, L., Tsai, C.-J., Byrne, D.H., Smulders, M.J.M., Foucher, F. & Debener, T. 2011 Towards a unified genetic map for diploid roses Theor. Appl. Genet. 122 489 500
Ueckert, J., Byrne, D.H., Crosby, K., Hodnett, G. & Stelly, D. 2015 The utilization of the polyploid nature of roses Acta Hort. 1064 73 78
U.S. Department of Agriculture 2015 Floriculture crops 2015 summary. 9 June 2019. <https://www.usda.gov/nass/PUBS/TODAYRPT/floran16.pdf>
Vineland Research and Innovation Centre 2013 The innovation report. Vineland Res. Innovation Ctr., Vineland Station, ON, Canada
Waliczek, T.M., Byrne, D.H. & Holeman, D.J. 2018 Opinions of landscape roses available for purchase and preferences for the future market HortTechnology 28 807 814
Zlesak, D.C. 2009 Pollen diameter and guard cell length as predictors of ploidy in diverse rose cultivars, species, and breeding lines Floricul. Ornamental Biotechnol. 3 53 70
Zuzek, K., Richards, M., McNamara, S. & Pellett, H. 1995 Performance of shrub and old garden roses at the Minnesota Landscape Arboretum. Minnesota Rpt., Univ. Minnesota, Agr. Expt. Sta., St. Paul, MN